1. Field of the Invention
The present invention relates to a light adjusting apparatus.
2. Description of the Related Art
In recent years, with improved high-quality performance of a portable equipment having an image pickup function, and a small-size optical apparatus such as a micro video scope, with regard to optical elements such as a lens, an aperture, there has been increasing demand for an application of a focusing lens, a variable aperture instead of a conventional fixed focusing lens and a fixed aperture stop, and further small-sizing (slimming) of such optical elements has been sought.
For example, in Japanese Patent Application Laid-open Publication No. Hei 10-20360, a coil which is formed on a printed circuit board and a light-quantity adjusting apparatus in which the coil is used have been described. In a diaphragm blade which is to be used here, a shaft which is a rotating shaft member of the diaphragm blade and a magnet are joined integrally. The shaft and the magnet which are joined integrally are rotatably installed in a bearing hole which has been formed in an upper and a lower substrate, and are rotated by imparting a torque by the coil. A peculiarity of the abovementioned structure is that while using a thin substrate, a coil which can maintain a strong magnetic field is prepared, and further, an extremely thin light adjusting apparatus can be prepared by using the coil.
However, in a structure as described in Japanese Patent Application Laid-open Publication No. Hei 10-20360, it is necessary to insert the shaft directly into a shaft hole of the diaphragm blade.
Consequently, when an attempt is made to link the shaft and the diaphragm blade by press fitting, there is a possibility of the diaphragm blade getting deformed (in axial direction) at the time of press fitting, and there is a possibility of assembling becoming extremely difficult.
When the diaphragm blade is made further smaller (thinner) with the aim of small-sizing (slimming), such deformation of the diaphragm blade may occur all the more remarkably.
Particularly, in an extremely thin light adjusting apparatus as in this field of technology, when an outer diameter φ of the shaft is about 0.2 mm, and a thickness of the diaphragm blade is approximately 50 μm, since an effect of machining tolerance which cannot be eliminated easily becomes substantial, it is desirable to adopt a structure which hardly has an effect of the machining tolerance even when it exists.